Method of manufacturing paving blocks



Mam}! 1937- s. P. MILLER METHOD OF MANUFACTURING PAVING BLOCKS Filed Sept 24, 192s 'S MILLER ATTORNEY Patented Mar. 9, 1937 UNI-TED STATES PATENT OFFICE METHOD OF MANUFACTURING PAVING BLOCKS of New Jersey Application September 24, 1928, Serial No. 308,058

3 Claims.

The present invention has for an object to provide an improved paving or surfacing material and an improved method of manufacturing the same.

In the manufacture of prepared roofings which comprise felt saturated and coated with asphalt a certain amount of waste is always made. Part of this waste results from the cutting of the prepared roofing into strips or individual shingles, part is made up of waste roofing resulting from tearing, puncturing or other defects, and part results from rejection of material failing to pass inspection. I have found that these waste products can be molded and compressed to form blocks useful as paving or flooring material. The products may conveniently be made into blocks to be laid in any suitable support and such an embodiment will be more particularly described for the purpose of illustrating the prin- 2Q ciples of the invention.

In the production of single or strip asphalt shingles the trimmings commonly comprise small narrow strips of the roofing material. These strips may be laid symmetrically in molds g5 and compressed or the strips may be placed in the molds without any attempt at symmetrical arrangement and compressed. Also the strips may be shredded and compressed. Further, if the waste to be compressed is made up of sheets of relatively large irregular pieces, preferably it is cut into strips or shredded before being compressed. However, if large molded units are to be produced it may not be necessary to cut the material into strips or to shred it before compressing the material.

If the waste material has been saturated with asphalt but not coated it may in some cases be necessary to add asphalt to the waste material in order to supply sufficient binder to insure a satisfactory molded block or form. In some cases the saturated felt contains sufiicient asphalt to bind the individual pieces together to form a satisfactory block.

In the drawing forming a part hereof Fig. 1 is a perspective view of a paving block having the material arranged longitudinally of the block;

Fig. 2 is a perspective view of a block showing a modified arrangement of the material;

Fig. 3 is a perspective View of a block showing another modified arrangement of the material from which the paving block is formed;

Fig. 4 is a perspective view of .a block having the material therein positioned without any attempt at symmetrical arrangement;

Fig. 5 is a perspective view of a block wherein the material was shredded before being compressed; and

Fig. 6 is a perspective view of a stair tread.

The preferred method of forming a paving 5 block involves assembling suitable impregnated and/or coated felt in a mold and compressing it to form a hard compact paving block. The block shown in Fig. 3 may be formed by assembling pieces of roofing material impregnated with as- 10 phalt, tar or other suitable bituminous material in layers in the mold, separate strips preferably being laid to lie in different directions as indicated in the drawing, wherein strips 5 are shown as extending longitudinally of the block and 15 strips 6 extending transversely. The material shown is typical roofing material trimmings and the pieces are assembled with the surface side of one piece of material in contact with the smooth side of the next piece.

The block shown in Figs. 1 and 2 is formed from felt strips which are placed symmetrically in molds and compressed, the strips I extending longitudinally of the block. In Fig. 1 the strips 7 are shown extending longitudinally and posi- 25 tioned with the surface side of one piece of material in contact with the smooth side of the next piece. In Fig. 2 the strips 1 are shown positioned in a plurality of piles, the strips in each pile extending with the surface side of one piece 30 in contact With the smooth side of the next piece.

The block shown in Fig. 4 is formed by placing the strips 9 in the mold without any attempt at symmetrical arrangement and thereafter com- 35 pressing the strips. In Fig. 5 the block is shown as formed from felt which has been more or less shredded and the small pieces ID are placed in the mold and compressed to form the finished paving product, 40

The temperature and pressure at which the compressing operation takes place will depend upon the character of the raw material and the character of the desired resultant product. When roofing felt impregnated with asphalt or tar is 5 used the blank can be heated sufiiciently to soften the impregnating material so that the bitumen contained in and on adjacent pieces of material flows or is forced together and forms a substantially continuous phase within which the fibers of the roofing felt are embedded as reinforcing material. For example, in forming paving blocks four inches wide by eight inches long and two inches thick the blank may be heated to a temperature of approximately 200 Fahr. for a 55 period of seven minutes. Preferably the temperature should not exceed 225 Fahr. The pressure applied will depend upon the density desired but may approximate 1,000 lbs. per square inch or upwards. An effective paving block can be produced even if lesser pressures and lower temperatures are employed. In fact, the paving blocks of Figs. 3 and 4 have been formed by cold pressing the felt, but preferably the mold and felts are heated. If desired the finished blocks may be cooled while still under pressure.

Prepared roofings are commonly made with smooth surfaces and also with surfaces coated with slag, slate or the like. Waste material coated with slag, slate or the like may be used for the production of satisfactory blocks; also slag, slate or the like may be added to the waste prior to compression to increase the density and wearing qualities of the block.

The top surface of the block may be provided with a more durable surface by the addition of gravel, slag or the like, thereto. Desired decorative effects may be.obtained by coating the top other desired surface of the block with slag, slate or the like.

The blocks may be used as are ordinary building brick or wood paving blocks and may be laid dry. The joints between blocks may then be filled by coating with asphalt or other binder. Also the blocks may be dipped in asphalt or other binder and laid in the thus applied cement.

The blocks have the desirable characteristics of being wear-resistant, resilient and waterproof. They are capable of withstanding heavy loads and are substantially noiseless, particularly as compared with concrete or other hard pavements when subjected to moving steel shod vehicles.

My invention may be used in connection with the production of stair treads. In the manufacture of such articles preferably a steel or 0th?" metallic form I! (Fig. 6) is placed in the mold and the waste products compressed into this form. The resultant product which may be used as a stair tread has several desirable characteristics.

It is light in weight, resistant to wear and to a large extent reduces the danger of slipping on the part of the user. Steel forms may be of various shapes and designs to give the desired strength and rigidity.

The foregoing particular description is illustrative merely and is not intended to define the invention.

I claim:

1. The process of manufacturing a composition paving block for floors, roads, pavements and the like subjected to wear by pedestrian or vehicular traflic, which comprises assembling bitumen-impregnated felt together with solid mineral matter so as to form a mass of said felt having the mineral matter distributed therein and of a volume substantially greater than the volume desired in the finished block, and compressing said mass under high pressure to form a dense, resilient, wear-resistant block.

2. The process of manufacturing a composition paving block for floors, roads, pavements and the like subjected to wear by pedestrian or vehicular traffic, which comprises assembling scraps of bitumen-impregnated, solid mineral surfaced roofing felt in a mold to form a mass of said scraps having the mineral material distributed therein and of a volume substantially greater than the volume desired in the finished block, and compressing said mass under high pressure to form a dense, resilient, wear-resistant block.

3. The process of manufacturing a composition paving block for floors, roads, pavements and the like subjected to wear by pedestrian or vehicular traffic, which comprises heterogeneously arranging bitumen-impregnated, solid-mineral-surfaced roofing scraps in a mold to form a mass of said scraps having the mineral matter distributed therein and of a volume substantially greater than the volume desired in the finished block, heating the mass of scraps and subjecting it to a pressure of at least 1,000 pounds per square inch to form a dense, resilient, wear-resistant block.

STUART PARMELEE MILLER. 

